1. Field of the Invention
The present invention relates to cooling systems, and more particularly to cooling systems used with racks and enclosures used for data processing, networking and telecommunications equipment.
2. Discussion of Related Arts
Communications and information technology equipment is commonly designed for mounting on racks and for housing within enclosures (often included in the term “rack”). Equipment racks are used to contain and to arrange communications and information technology equipment, such as servers, CPUs, data processing equipment, networking equipment, telecommunications equipment and storage devices, in relatively small wiring closets as well as equipment rooms and large data centers. An equipment rack can be an open configuration or can be housed within a rack enclosure, although the enclosure may be included when referring to a rack. A standard rack typically includes front-mounting rails to which multiple units of equipment, such as servers and CPUs, are mounted and stacked vertically, for example, within the rack. A standard rack at any given time can be sparsely or densely populated with a variety of different components (e.g., server blades) as well as with components from different manufacturers.
Most rack-mounted communication and information technology equipment consumes electrical power and generates heat, which can have an adverse effect on the performance, reliability and useful life of the equipment components. In particular, rack-mounted equipment housed within an enclosure is particularly vulnerable to heat build-up and hot spots produced within the confines of the enclosure during operation. The amount of heat generated by a rack of equipment is dependent on the amount of electrical power drawn by equipment in the rack during operation. The amount of heat a given rack or enclosure can generate, therefore, may vary considerably from a few tens of watts up to about 40,000 watts, and this upper end continues to increase with the constant evolution of this technology.
In some embodiments, rack-mounted equipment is cooled by drawing air along a front side or air inlet side of a rack, drawing air through its components, and subsequently exhausting air from a rear or vent side of the rack. Airflow requirements to provide sufficient air for cooling can vary considerably as a result of different numbers and types of rack-mounted components and different configurations of racks and enclosures.
Equipment rooms and data centers are typically equipped with an air conditioning or cooling system that supplies and circulates cool air to racks. One such cooling system employs a raised floor to facilitate air conditioning and circulation systems. Such systems typically use open floor tiles and floor grills or vents to deliver cool air from an air passageway disposed below the raised floor of an equipment room. Open floor tiles and floor grills or vents are typically located in front of equipment racks, and along aisles between rows of racks arranged side-by-side.
One cooling system is disclosed in co-pending U.S. patent application Ser. No. 10/993,329, entitled IT EQUIPMENT COOLING, filed on Nov. 19, 2004, which is owned by the assignee of the present application and is incorporated herein by reference. In one embodiment, this system includes one or more main condensing modules, a coolant distribution section, a heat exchanger module section, and a backup coolant section. The coolant distribution section includes a bulk storage tank, an evacuation/recovery pump, a manifold and hoses. The condensing module(s) sends cool liquid to the heat exchanger module section by means of the distribution section, where the liquid is evaporated, into gas by hot air from the IT equipment, and the vapor coolant is returned to the main condensing module(s). At the main condensing module(s), a primary cooling portion cools the heated vapor coolant back into a liquid for supply to the heat exchanger module section by the distribution section. In the case of a failure of one of the primary condensing modules, a secondary condensing module can cool and condense the heated vapor coolant if power has not failed to the system. If power has failed to the system, the backup coolant section, which may include several ice storage tanks, can continue to cool, without using high power consumption vapor compression systems, the heated coolant from the heat exchange module section for the duration of battery life or depletion of ice storage of the system.